1. Field of the Invention
The present invention relates to the improvement of a driving force interrupting mechanism.
2. Description of Background Art
As a driving force interrupting mechanism for interrupting driving force to one of the front-wheel side and the rear-wheel side in a state in which driving force can be transmitted to the other of the front-wheel side and the rear-wheel side to switch a four-wheel-drive state and a two-wheel-drive state in a conventional type four-wheel drive vehicle, a hub clutch is known (for example, refer to JP-A No. 289724/1989).
FIG. 1A of JP-A No. 289724/1989 will be described below. Reference numerals in the patent application are used as they are.
An axle 1 is a member which is fitted to a spindle 27 as the spindle can be rotated and to the end of which a driving gear 3 is coupled via a spline.
A housing 5 is arranged so that the housing encircles the axle 1 and the driving gear 3, is attached to the spindle 27 so that the spindle can be rotated, a wheel 15 is attached to a hub 9, a slide gear 55 is connected to an inner face of the housing 5 via a spline and is attached so that the slide gear can be axially moved.
The axle 1 and the wheel 15 are coupled or the axle 1 and the wheel 15 are uncoupled by coupling or uncoupling the driving gear 3 and the slide gear 55.
The slide gear 55 is pressed in a direction in which the slide gear and the driving gear 3 are coupled by a shift spring 65 and is pressed in a direction in which the slide gear and the driving gear 3 are uncoupled by a piston member 69 and a return spring 85.
In the above-mentioned technique, as the shift spring 65, the piston member 69 and the return spring 85 are required to move the slide gear 55, structure for connecting or disconnecting a power transmission path is made complex, large space is occupied, the cost of the driving force interrupting mechanism is increased, and the driving force interrupting mechanism is large-sized.